Preprints
https://doi.org/10.5194/cp-2021-73
https://doi.org/10.5194/cp-2021-73

  18 Jun 2021

18 Jun 2021

Review status: this preprint is currently under review for the journal CP.

Simulating glacial dust changes in the Southern Hemisphere using ECHAM6.3-HAM2.3

Stephan Krätschmer1, Michelle van der Does1, Frank Lamy1, Gerrit Lohmann1,2, Christoph Völker1, and Martin Werner1 Stephan Krätschmer et al.
  • 1Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
  • 2Physics Department, University of Bremen, Bremen, Germany

Abstract. Mineral dust aerosol constitutes an important component of the Earth’s climate system, not only on short timescales due to direct and indirect influences on the radiation budget, but also on long timescales by acting as a fertilizer for the biosphere and thus affecting the global carbon cycle. For a quantitative assessment of its impact on the global climate, state-of-the-art atmospheric and aerosol models can be utilized. In this study, we use the ECHAM6.3-HAM2.3 model to perform global simulations of the mineral dust cycle for present-day (PD), pre-industrial (PI) and Last Glacial Maximum (LGM) climate conditions. The intercomparison with marine sediment and ice core data as well as other modeling studies shows that the obtained annual dust emissions of 1221, 923 and 5159 Tg for PD, PI and LGM, respectively, generally agree well with previous findings. Our analyses focussing on the Southern Hemisphere suggest that over 90 % of the mineral dust deposited over Antarctica are of Australian or South American origin during both PI and LGM. However, contrary to previous studies, we find that Australia contributes a higher proportion during the LGM, which is mainly caused by changes in the precipitation patterns. Obtained increased particle radii during the LGM can be traced back to increased sulphate condensation on the particle surfaces as a consequence of longer particle lifetimes. The meridional transport of mineral dust from its source regions to the South Pole takes place at different altitudes, depending on the grain size of the dust particles. We find a trend of generally lower transport heights during the LGM compared to PI as a consequence of reduced convection due to colder surfaces, indicating a vertically less extensive Polar Cell.

Stephan Krätschmer et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • CC1: 'Paper needs to discuss data on provennce of Antarctic dust in LGM', Eric Wolff, 22 Jun 2021
    • AC1: 'Reply on CC1', Stephan Krätschmer, 30 Jul 2021
  • RC1: 'Comment on cp-2021-73', Anonymous Referee #1, 06 Jul 2021
    • AC2: 'Reply on RC1', Stephan Krätschmer, 20 Sep 2021
  • RC2: 'Comment on cp-2021-73', Anonymous Referee #2, 30 Jul 2021
    • AC3: 'Reply on RC2', Stephan Krätschmer, 20 Sep 2021

Stephan Krätschmer et al.

Stephan Krätschmer et al.

Viewed

Total article views: 639 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
498 121 20 639 5 10
  • HTML: 498
  • PDF: 121
  • XML: 20
  • Total: 639
  • BibTeX: 5
  • EndNote: 10
Views and downloads (calculated since 18 Jun 2021)
Cumulative views and downloads (calculated since 18 Jun 2021)

Viewed (geographical distribution)

Total article views: 508 (including HTML, PDF, and XML) Thereof 508 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 18 Oct 2021
Download
Short summary
We use an atmospheric model coupled to an aerosol model to investigate the global mineral dust cycle with a focus on the Southern Hemisphere for warmer and colder climate states and compare our results to observational data. Our findings suggest Australia to be the predominant source of dust deposited over Antarctica during the last glacial maximum. Additionally, we find that the southward transport of dust from all sources to Antarctica happens on lower altitudes in colder climates.